Human CD59 peptide

Objective Gut-derived innate lymphoid cell 3 (ILC3) has been shown to participate in the pathogenesis of ankylosing spondylitis (AS). CX(3)CR1+ mononuclear phagocytes (MNPs) have been demonstrated to modulate ILC3 function in the gut. This study was undertaken to investigate the role of proinflammatory CX(3)CR1+CD59+ MNPs in modulating ILC3 function in AS patients. Methods MNP subsets in the blood of AS patients and controls were analyzed by flow cytometry. The presence of CX(3)CR1+CD59+ cells in tissue was confirmed by confocal microscopy. Expression of the proinflammatory chemokines CX(3)CL1 and CCL2 and decoy receptor 6 (DcR-6) was analyzed. Peripheral CX(3)CR1+CD59+ cells were cocultured with ILC3, and changes in their frequency were evaluated by flow cytometry. Transcriptome analysis of circulating CX(3)CR1+ monocytes was also performed. Results DcR-6 deficiency and CCL2 overexpression were observed in inflamed tissues from AS patients. In the gut, the proinflammatory CX(3)CR1+CD59+ MNP population was expanded, correlated with the presence of bacteria, and produced high levels of tumor necrosis factor-like molecule 1A (TL1A) and interleukin-23 (IL-23). MNPs positive for CD11b, CD11c, and major histocompatibility complex class II, predominantly expressing CX(3)CR1, were also expanded in the small intestines of treatment-naive SKG relative to BALB/c mice. The frequency of gut-derived CX(3)CR1+CD59+CCR9+TL1A+IL-23+ MNPs was significantly higher in the peripheral blood and synovial fluid of AS patients than controls. CCR9+CX(3)CR1+CD59+ monocytes were also expanded in AS synovial and bone marrow samples. Transcriptome analysis of isolated CX(3)CR1+CD59+ monocytes demonstrated a specific proinflammatory profile in AS. Isolated proinflammatory CX(3)CR1+CD59+ MNPs from AS patients induced the expansion and activation of ILC3. Conclusion Proinflammatory CX(3)CR1+CD59+TL1A+IL-23+ MNPs are expanded in AS patients and display a specific proinflammatory transcriptome profile. Given the ability of these cells to support ILC3 expansion, they may promote a sustained proinflammatory status in AS.

Advances in animal transgenesis may allow using xenogeneic chondrocytes in tissue-engineering applications for clinical cartilage repair. Porcine cartilage is rejected by humoral and cellular mechanisms that could be overcome by identifying key molecules triggering rejection and developing effective genetic-engineering strategies. Accordingly, high expression of alpha 1,2-fucosyltransferase (HT) in xenogeneic cartilage protects from galactose alpha 1,3-galactose (Gal)-mediated antibody responses. Now, we studied whether expression of a complement inhibitor provides further protection. First, porcine articular chondrocytes (PAC) were isolated from non-transgenic, single and double transgenic pigs expressing HT and moderate levels of human CD59 (hCD59) and their response to human serum was assessed. High recombinant expression of human complement regulatory molecules hCD59 and hDAF was also attained by retroviral transduction of PAC for further analyses. Complement activation on PAC after exposure to 20 % human serum for 24 hours mainly triggered the release of pro-inflammatory cytokines IL-6 and IL-8. Transgenic expression of HT and hCD59 did not suffice to fully counteract this effect. Nevertheless, the combination of blocking anti-Gal antibodies (or C5a) and high hCD59 levels conferred very high protection. On the contrary, high hDAF expression attained the most dramatic reduction in IL-6/IL-8 secretion by a single strategy, but the additional inhibition of anti-Gal antibodies or C5a did not provide further improvement. Notably, we demonstrate that both hCD59 and hDAF inhibit anaphylatoxin release in this setting. In conclusion, our study identifies genetic-engineering approaches to prevent humoral rejection of xenogeneic chondrocytes for use in cartilage repair.